A particle moves in \( x{-}y \) plane under the influence of a force \( \vec{F} \) such that its linear momentum is \( \vec{p}(t)=\vec{i}\cos(kt)-\vec{j}\sin(kt) \). If \( k \) is constant, the angle between \( \vec{F} \) and \( \vec{P} \) will be:
\( \frac{\pi}{6} \)
\( \frac{\pi}{2} \)
\( \frac{\pi}{4} \)
\( \frac{\pi}{3} \)